Concept:
Saline irrigation water contains dissolved substances known as salts. In much of the arid and semi-arid areas most of the salts present in irrigation water are chlorides, sulphates, carbonates, and bicarbonates of calcium magnesium, sodium, and potassium.
While salinity can improve soil structure, it can also negatively affect plant growth and crop yields.
Sodicity refers specifically to the amount of sodium present in irrigation water. Irrigating with water that has excess amounts of sodium can adversely impact soil structure, making plant growth difficult.
Highly saline and sodic water qualities can cause problems for irrigation, depending on the type and amount of salts present, the soil type being irrigated, the specific plant species and growth stage, and the amount of water able to pass through the root zone.
Causes of soil salinity and sodicity:
1. Major reason for bringing in excessive salts in the plant root zone is the use of excessive irrigation water or having very wet weather conditions (excessive rains), which are man-made and natural respectively.
2. The primary natural cause for these two is the parent material of the soils within the state and the underlying sodium-rich shale that is present in the bedrock below the soil sediments.
3. Irrigation mismanagement
4. Poor land levelling
5. Leaching without adequate drainage